[Build] Add back sources to Eclipse-SDK product

The sources of all contained bundles were accidentally removed from the
eclipse-SDK product in
- #3549

That is because the p2-repository assembled for the eclipse-SDK product
didn't contain sources before, as that repository is not used further.
But now that the product is materialized from that p2-repository (since
that mentioned change), sources went missing in the product itself too.

Consequently the property 'repository.includeAllSources' must now be
true if 'product.installSources' is true. Otherwise the latter has no
effect. If no sources are available in the source-repository, of course
Tycho cannot install them.

Additionally remove dependencies again from eclipse-junit-tests product.
They were added unintentionally in the mentioned change, too.

Fixes
- eclipse-jdt/eclipse.jdt.core#4684

Author: HannesWell

products/eclipse-junit-tests/pom.xml

@@ -39,7 +39,17 @@
       </resource>
     </resources>
 
-
+    <pluginManagement>
+      <plugins>
+        <plugin>
+          <groupId>org.eclipse.tycho</groupId>
+          <artifactId>tycho-p2-repository-plugin</artifactId>
+          <configuration>
+            <includeAllDependencies>false</includeAllDependencies>
+          </configuration>
+        </plugin>
+      </plugins>
+    </pluginManagement>
     <plugins>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>

products/eclipse-sdk/build.properties

@@ -2,6 +2,7 @@
 pom.model.property.product.id = org.eclipse.sdk.ide
 pom.model.property.product.rootFolder = eclipse
 pom.model.property.product.rootFolder.macosx = Eclipse.app
+pom.model.property.repository.includeAllSources = true
 pom.model.property.product.installSources = true
 
 pom.model.property.eclipse.signing.skip = false

products/pom.xml

@@ -38,6 +38,9 @@
 	<!-- TODO: Move site like products (e.g. equinox-sdk and junit-tests) into sites folder, which also avoids inheriting (for them) unwanted configuration?-->
 
 	<properties>
+		<!-- If product.installSources is set to true,
+		repository.includeAllSources must always be true too.
+		Otherwise the former has no effect (because source=repository). -->
 		<product.installSources>false</product.installSources>
 		<repository.includeAllSources>false</repository.includeAllSources>
 	</properties>